Bladder Cancer in Dogs
It's devastating to find out that your dog has bladder cancer. While this form of cancer is uncommon in dogs, it is aggressive and often fatal. Certain breeds are more likely to develop bladder cancer, and obesity is a known risk factor in all dogs. Fortunately, treatments are available that can improve the quality and duration of a dog's life, and early detection may expand treatment options.
What Is Bladder Cancer?
Bladder cancer is a serious form of cancer that affects the urinary tract of dogs. Transitional cell carcinoma (TCC) is the most common type of bladder tumor seen in dogs.1 Also called urothelial carcinoma, this malignant tumor grows from the transitional epithelial cells lining the bladder and invades the bladder walls. Tumors limit bladder function and capacity and may even cause urinary blockage. TCC is usually found in the bladder but can also be found in the urethra, kidneys, ureters, and prostate. This cancer may also spread to the lymph nodes and other organs in the body such as the lungs and liver.
Symptoms of Bladder Cancer in Dogs
The signs of bladder cancer are very similar to the signs of urinary tract infections in dogs, but they do not respond to treatment.
Symptoms
Blood in the urine (hematuria)
Straining to urinate (stranguria)
Abnormally frequent urination (pollakiuria)
Decreased urine output (oliguria)
Painful urination (dysuria)
Inappropriate urination/urinary accidents in the house
Inability to urinate at all
Urinary incontinence
In the early stages of bladder cancer, it may appear as if the dog has a UTI. However, these urinary tract infections tend to recur and do not typically respond well to antibiotic therapy.
Bladder tumors result in pain and inflammation in the bladder, causing many dogs to urinate frequently, often in small amounts. Bloody or discolored urine may be seen as well. As tumors grow, urination becomes increasingly difficult, leading to straining and possible obstruction.
Causes of Bladder Cancer
The exact cause of bladder cancer in dogs is not known, but certain risk factors have been identified.
Dog Breed: Compared to mixed-breed dogs, Scottish terriers have a 20-fold risk of developing bladder cancer. Other high-risk dog breeds include Eskimo, Shetland sheepdog, West Highland white terrier, keeshond, Samoyed, beagle, and dalmatian.
Obesity
Female dogs
History of spay or neuter
Exposure to insecticides and lawn chemicals2
Diagnosis of Bladder Cancer
It's important to visit the veterinarian at the first sign of urinary problems in your dog. Even simple urinary tract infections can become serious if left untreated. Because bladder cancer signs are similar to those of UTIs, it's important to involve a veterinarian so the proper diagnostic tests can be performed.
Your veterinarian will recommend diagnostic tests after discussing your dog's history and performing a physical examination. This typically begins with a urinalysis to evaluate the urine. Blood tests may be recommended to evaluate blood cells and organ function. Abdominal radiographs (X-rays) and ultrasound may be performed to visualize the bladder and surrounding organs.
After diagnosing bladder cancer, staging may be recommended to determine if cancer has metastasized (spread). Staging typically includes diagnostic imaging of the chest and abdomen to look for evidence of cancer in the lungs or other organs. A CT scan or MRI may be recommended at this point.
Treatment
Bladder cancer treatment may require a multimodal approach, meaning several different types of treatments are applied to manage the disease. A diagnosis of bladder cancer typically warrants referral to one or more board-certified veterinary specialists, including an oncologist and a veterinary surgeon. Unfortunately, there is no cure for bladder cancer in dogs.
Surgical Treatment
Surgery may be recommended to remove all or part of the bladder tumor (or tumors). It is difficult to completely excise bladder tumors without removing essential parts of the bladder and urinary tract, so debulking (partial removal) may be the only option. Bladder cancer is rarely cured with surgery. However, surgery may slow the progression and relieve some of the symptoms of bladder cancer in dogs.
Chemotherapy
Bladder cancer does not typically respond well to chemotherapy, but certain chemotherapy protocols can extend survival time. Chemotherapy is typically administered every week or two for several months.
Radiation Therapy
Radiation therapy may be a palliative option for dogs with bladder cancer. This means that the treatment may relieve pain and decrease symptoms, but it will not cure the disease. In some cases, the side effects of radiation therapy are too severe to justify continued treatment.
Nonsteroidal Anti-Inflammatory Drug Therapy
NSAIDs, particularly piroxicam, have been quite effective at managing bladder cancer and increasing life expectancy. Some dogs will go into remission with NSAID therapy. In some cases, NSAIDs are used alone, but more often they are used in conjunction with one or more of the other treatment options.
Prognosis
In general, bladder cancer is highly aggressive and has a poor prognosis. The survival rate for dogs with bladder cancer will vary depending on the stage of the disease at diagnosis. In general, dogs without treatment will succumb to the disease in a matter of weeks to months, depending on the stage. Dogs with NSAID treatment in conjunction with multimodal treatment may survive up to a year or longer.1
How to Prevent Bladder Cancer
Bladder cancer may not be preventable in many cases, but there are some ways to reduce the risks. Keep your dog healthy and at an ideal weight. Minimize your dog's exposure to chemicals like pesticides and lawn treatments. Be sure to bring your dog to the vet for wellness examinations as recommended; your vet may be able to identify a health problem before symptoms develop.
Early screening is available in the form of gene testing. A genetic mutation called BRAF V595E is found in about 80% of dogs with bladder cancer. Some laboratories offer a PRC test for this mutation. A negative result will not guarantee your dog is safe from bladder cancer, but a positive result may help you take early action.3 Ask your vet about the availability of this test.
